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ATEL # 2010; A..A. Mahabal, A.J. Drake, S.G. Djorgovski, M.J. Graham, R. Williams, W. Max-Moerbeck (Caltech); M. Catelan (PUC, Chile); E.C. Beshore, S.M. Larson, A. Gibbs, R. Kowalski, A. Boattini, R. Hill (LPL/UA); E. Christensen (Gemini Observatory); V. Mohan, A.N. Ramaprakash, A.K. Kembhavi (IUCAA);
on 10 Apr 2009; 22:45 UT
Distributed as an Instant Email Notice (Request for Observations)
Password Certification: Ashish Mahabal (email@example.com)
Subjects: Optical, Nova, Supernova, Transients
The Catalina Real-time Transient Survey (CRTS) has spectroscopically characterized CSS080928:160837+041626 (ATel 1768) as a Type IIn SN at z~0.041 using the SMARTS 1.5m telescope using Observations taken on March 27th UT with the following results:
The object was first marked as a transient by CRTS on 2008-09-28 (unfiltered mag=17.7). It was also present in the 2007-09-13 images, but blended with the brighter star nearby and hence not detected as a transient. Palomar-Quest images from 2007-02-24 do not reveal the presence of the SN. GALEX data from 2008-06-05 shows a well-detected source at this location (NUV 19.93+/-0.04, FUV 21.18+/-0.09). It was not seen in AIS images from 2004-05-17 indicating a brightening in NUV by at least 2.5 mags. Coadded images from SDSS (all filters) reveal the presence of a possible faint host at the location. Assuming that the galaxy has r=23, at z=0.041 it translates to M_r=~-13, almost a 100 times dimmer than the LMC.
Palomar 60-inch (P60) data form 2009-03-21 reveals that it is still bright (r=17.60+/-0.04). It has stayed bright for over 500 days, and rising much of the time. In fact the SMARTS spectrum with its Balmer lines (strong H-alpha, H-beta, H-gamma), He I lines (5876, 7065 and possibly others), and an absence of Oxygen lines reveals it to be much more like SN1994Y at T=30 days (Filipenko A.V., ARAA, 1997, 35, 309-355, Fig. 14). There is also some evidence of Fe-I emission and the H-beta shows a P-Cygni like profile. The maximum P60 r-band magnitude was ~17.2 suggesting an absolute magnitude ~-18.8. The evidence is consistent with a type IIn supernova possibly with high density circumstellar material.
Additional observations are requested.
All current candidate and confirmed SNe as well as finding charts can be found here.
R. E. Rutledge , Editor
ATEL Mirror v1.0 Updates